The invention relates to a lens hood for a photographic lens, which lens hood is axially displaceable out of a position of use into a position of rest and is connected to the lens in a manner to prevent rotation therebetween.
Swiss Patent No. 236,399 discloses a lens hood of this type. This consists of a stationary part with a bayonet closure and a displaceable part. The stationary part is fixed to the camera independently of the lens and possesses guide pins on which the displaceable part can slide axially from a position of rest into a working position. In both positions, the displaceable part is locked by means of springs against unintentional displacement. In the working position of the lens hood, the stationary part permits lateral access so that the aperture and distance can be set on the lens. This known lens hood is relatively bulky. In order to attach filters, which are screwed into the frontal thread on the accessory mount of the lens, the lens hood has to be removed from the lens.
Swiss Patent No. 446,877 discloses a lens hood for photographic lenses, particularly of short focal length, which comprises a set of mutually interchangeable masks of rectangular cross-section. The individual masks can be connected, by means of a plurality of balls under spring pressure, to a mounting ring which is screwed into the frontal thread of the accessory mount for the lens. Each mask is provided with a gripping element which allows the mask to be twisted for an upright or landscape format. The lens hood is arranged directly in front of the lens in order to mask the circular segments of the lens which are not required to form the image. The addition of filters or other attachments to the lens is not possible when this lens hood is used.